git-filter-repo/Documentation/Contributing.md

Welcome to the community!

Contributions need to meet the bar for inclusion in git.git. Although filter-repo is not part of the git.git repository, I want to leave the option open for it to be merged in the future. As such, any contributions need to follow the same guidelines for contribution to git.git, with a few exceptions:

• While I hate GitHub PRs (as others point out, it's mind-boggling in a bad way that web-based Git hosting and code review systems do such a poor job), git-format-patch and git-send-email can be a beast and I have not yet found time to modify Dscho's excellent GitGitGadget to work with git-filter-repo. As such:
  • For very short single-commit changes, feel free to open GitHub PRs.
  • For more involved changes, if format-patch or send-email give you too much trouble, go ahead and open a GitHub PR and just mention that email didn't work out.
• If emailing patches to the git list:
  • Include "filter-repo" at the start of the subject, e.g. "[filter-repo PATCH] Add packaging scripts for uploading to PyPI" instead of just "[PATCH] Add packaging scripts for uploading to PyPI"
  • CC me instead of the git maintainer
• Git's CodingGuidlines for python code are only partially applicable:
  • python3 is a hard requirement; python2 is/was EOL at the end of 2019 and should not be used. (Commit 4d0264ab72 ("filter-repo: workaround python<2.7.9 exec bug", 2019-04-30) was the last version of filter-repo that worked with python2).
  • You can depend on anything in python 3.5 or earlier. I may bump this minimum version over time, but do want to generally work with the python3 version found in current enterprise Linux distributions.
  • In filter-repo, it's not just OK to use bytestrings, you are expected to use them a lot. Using unicode strings result in lots of ugly errors since input comes from filesystem names, commit messages, file contents, etc., none of which are guaranteed to be unicode. (Plus unicode strings require lots of effort to verify, encode, and decode -- slowing the filtering process down). I tried to work with unicode strings more broadly in the code base multiple times; but it's just a bad idea to use an abstraction that doesn't fit the data.
  • I generally like PEP 8, but used two-space indents for years before learning of it and have just continued that habit. For consistency, contributions should also use two-space indents and otherwise generally follow PEP 8.

There are a few extra things I would like folks to keep in mind:

• Please test line coverage if you add or modify code

  • make test will run the testsuite under coverage3 (which you will need to install), and report on line coverage. Line coverage of git-filter-repo needs to remain at 100%; line coverage of contrib and test scripts can be ignored.

• Please do not be intimidated by detailed feedback:

  • In the git community, I have been contributing for years and have had hundreds of patches accepted but I still find that even when I try to make patches perfect I am not surprised when I have to spend as much or more time fixing up patches after submitting them than I did figuring out the patches in the first place. git folks tend to do thorough reviews, which has taught me a lot, and I try to do the same for filter-repo. Plus, as noted above, I want contributions from others to be acceptable in git.git itself.